Improvement in dry-docks



dini-ted Staten geen omite;

Letters Patent No. 102,554, (lated May 3, 18.70.

.IMPROVEMENT IN DRY-Docks.

The Schedule referred to in these Letters Patent and making part of the,same.

To all, whom Iit may concern:

Be 'it known that I, WILLIAM J oNns, of the city, county, and State ofNew York, have invented certain new and useful Improvements in BalanceDry-Docks; and I do hereby declare the following to be a full, clear,and exact description thereof, sutlcient to enable those skilled iu theart to which my invention appertains to fully understand and to make anduse the same, reference being had to the accompanying drawings formingpart of this specification, and in which- Figure 1, sheet l, is a groundplan of a balance dry-dock, showing the gates, bulk-heads, and tanks;Figure 2, sheet 2, represents a transverse section of the dock; and

Figure'3, sheet 3, is a side elevation of one-half of the dock.

Under the old system of raising a balance dry-dock,

with Orwthout avessel thereon, the sinking-gates must be and are keptclosed, and 4the whole ofthe water that all the' tanks contain must bepumped out of tanks as the dock rises; and when the dock rol-ls `orlists over to one side, (which is a frequent occurrence, especially inraising ships of very heavy tonnage,) there is no way to restore theequilibrium but by opening the aforesaid sinking-gatesto readmit water,and stopping the machinery on the lighter side, which sometimes causes adelay of several days before a ship can be raised. The cause of thisdiicultyis the system heretofore practised of pumping out the water fromthe upper part of the side tanks, where there is a very small space lof'lifting power, and the whole body'ot' water in the lower part of thedock inolines to roll to the heavier side. v

Another diiculty heretofore experienced in raising docks of this classis the bending of the upper portion or sides 0f the dock inward, whichis very injurious, not 'only to the dock itself, but also to the shipthat is on it, by causing the upper shores, which support the ship 011either side on even keel, to press with tremendous force against thevessel. This diiiiculty arises from the water being taken ont of theside tanks iirst, leaving the whole weight of the water contained in thecentral compartments, together with the weight of the ship,restingentirely on the center of the dock, thus straining the latter tosuch an extent as to make the bottom bend upward at the sides, whichnecessarily tends to draw the upper vportions vof the side tanks inwardtoward each other.

lo obviate these difficulties, and thus make vast .and new improvementsin the construction of balance dry-docks, is the object of my invention;andA It consists inthe arrangement ofthe central tanks, located whollybeneath the load, and the side tanks, with valves or gates connectingthe two sets, said of the pump-well and discharge-orifices, ashereinafter set forth. v

I wilLnow proceed lto describe the invention more fully in detail,referring to the accompanying drawings, wherein similar letters andfigures of reference indicate like parts in the several tigures.

In the drawings- A A represent the outside`tanks, which are very highand have the top inclined, as shown in tig. 2. These tanks are of suchaggregate capacity as to contain over one-halt` of all the water in thedock when it is sunk, preparatory to raising a ship. l l

B B are the. different compartments or tanks in the central part of thedock. The structure of these tanks, with their relative depth as regardsthe side tanks, is

' shown onsheet 2.

1 1 1, sheet 1, are the ordinary sinking-gates, which, under the oldsystem, are kept closed while the dock is being raised. y

3 3, 011 sheet 3, represent the discharge-gates or orifices from thepumps.

4 4, sheet 1, represent gates employed to conduct water from the sidetanks to the pumps.

5 5, on sheet 1, represent the ordinary gates connectingithecentral endtanks B with the side 'tanks A. These gates do not comeinto use untilvthe water in the side tanks is pumped out down to the level of theunder sideof the main deck, and it is impossible for the water in thecentral tanks to run into the side tanks until the water in the latterreaches the aforesaid level. This will be understood fromari-examination of tig. 2.

6 6 are gates by which a portion of the central tanks B communicate withthe pumps. shown in tig. l. v

An indicator, S, iig. 2, is employed to show when the ful'llifting poweris taken ont ofthe central tanks, and to tell the proper time forclosing the gates 6 and the outside delivery-gate, and open the gates 4when a ship of extra heavy weight .is being raised. 'Ihis indicatorconsists of a float attached to a small chain.

running over a pulley on the upper deck, with a small weight in theother end to balance the chain. A small perpendicular rod serves as aguide for the oat.

The line of gures marked from 12 to 20 on the side ot` the drawing No. 2shows the depth of water from the top of the keel-blocks.

In addition to the several series ot' gates above def scribed, which arecommon in balance dry-docks, I

Ihese gates are partnient's.

provide gates marked 7 7 on sheets 1 and 2, in the cross bnlkheadsbetween the central tanks B, so arranged as to connect all the saidtanks together when desired. These gates are operated from the upperdeck by means of a toothed wheel working in a rack on aiperpendicularrod, secured at the bottom to a triin the side tanks A to deliver itselffreely through` them, and all the sinking-gates 1 1 will be usedpartially for the same purpose.

Each of the gates 2 2 is so constructed as to deliver as much water asseveral, say'five, of the ordinary sinking-gates l 1. This is necessaryin order to keep the water down in the outside tanks as nearly aspossible level with thc water in which the dock is floating, so thatthere will be no weight of water in the outside tanks to be lifted withthe force of the central tanks. t

The dock is sunk by opening al1 the gates 1 l and 2 2,A to admit waterto the outside tanks A, whence it flows into the central tanks, thegates 5 being open. The gates 4 4, 6 6, and 7 7 g are all closed while`the dock is sinking.

lVhen about to raise the dock the gates 7 nre all opened, so that thecentral tanks are connected together, the gates (i are opened so as `topermit the' flow ot' water from the central tanks into the pumpwells,and the gates 5 are closed to sluit off the communication of the sidetanks with the central coml`he sinking-gates 1, self-delivery gates 2,and discharge-gates 3, from the pumps, all remain open while raising.

rlhe pumpsbeing now set in motion, water is drawn from the central tanksaud dischargedby way of the gates 3 3. NVater from the side tanks. alsoflows' out at these gates 3 by its own gravity. As the dock continues torise, the gates 2 2 gradually appear above the surface ofthe surroundingwater, andimmediately begin to discharge large volumes of Awater owin gfrom the side tanks hyits own gravity. The dock now rises very rapidly,the pumps still continuing to work, and

the gates 3 3, as well as the gates 2, at the same time discharging bygravity. Under these combined influences the sinking-gates 1, which arebelow the gates 2 2, are soon uncovered, and materially assist the gates2 2 by discharging water from the lower part of' the dock.

kBy my improvements the whole of the lifting power is transferred fromthe. outside tanks to the central compartments, upon which the weight ofa ship on the dock immediately rests, and consequently there will be anextended area of lifting space directly under the ship, which gives thedock the full lifting power at once, whereby the dock is raised veryrapidly, the water at the same time forcing itself` out from all theoutside tanks through the new self-delivery gates, and partially throughthe sinking-gates and the dischargeorices 3, asfabove described.

This self-discharging feature is very important, in view of the factthat hitherto all the wat-er had to be raised and thrown ont b'y pumps,whichis a` much slower, and consequently more expensive mode of raisinga dry-dock.

It will also be seen that, by the provision of the gates 2 2, which arealways open, the waterin the side tanks heilig nearly on a level withthe water on the outside ofthe dock, it will be utterly impossible forthe dock to. roll. v

Having tlnls described my invention,

Whatl claim as new, and desire to secure by Letters Patent, is-

1. A balance dry-dock, constructed with central tanks B B, separated bybulkheads, iu which are gates 7 7, side tanks A A, connected` with thecentral tanks by gates o 5, the self-delivery gates 2 2,

pump discharge-orifices 3 3, and sinking and self-de Witnesses HENRY W.CLARK, Hormon BARNARD.

